If there is a copy of the modified installer already on the selected volume, you will be asked if you want to re-use the existing data, or to build a new set.
- If you choose to build new, you will be asked to select a background colour for the graphical EFI boot phase.
- Grey
- Black
- If you choose to build new, then the old data is deleted and a fresh copy is generated.
Next: Rebooting...